public void DebugUpdate()
{
var t = debugTerrain.GetComponent <Terrain>();
int hr = t.terrainData.heightmapResolution;
float s = Time.realtimeSinceStartup;
var res = GenerateTile(worldToTerrain(debugTerrain.transform.position, t), hr, hr, true);
debugTerrain.SetTerrainData(res.heightmap, res.alphamap, debugTerrain.transform.position);
Debug.LogFormat("Generated terrain in {0} seconds", Time.realtimeSinceStartup - s);
}